Tips!!???

Okay SO! I've been going to the gym at least trying to run about a mile every other day (just the cardio makes me sweat and feel better) I've been relatively smaller my whole life but it's always my stomach I can never get quite down to size. Meaning, I just don't know how to tone my stomach. I'm not upset with my weight I just wish my stomach was flatter and less pudgy. Any work out ideas or meals/things I can eat to help with that?!